[Fix] Stop Fast from adding unrequested no-PR constraints to task briefs

[mrubens]

Summary

When a user asks a Session for a code change without saying anything about delivery, the Fast orchestrator sometimes appends its own "Do not create a PR or commit unless asked" constraint to the delegated task brief. The coding task obeys, finishes with local-only changes, and the user has to come back and ask for a PR separately. Nothing in the Fast prompt told the orchestrator what delivery policy to carry, so it invented one, overriding the standard workflow's default draft-PR delivery.

This adds one orchestration rule: carry the user's delivery instruction into the task brief only when they actually gave one, and otherwise leave delivery to the task's default workflow. It explicitly forbids inferring a no-commit/no-push/no-PR constraint from a detailed spec, listed constraints, requested tests, or a request to report results.

Changes

• packages/cloud-agents/src/server/fast-agent/fast-agent-prompt.ts: new Orchestration Policy bullet after the launch_task delegation rule.
• packages/cloud-agents/src/server/fast-agent/__tests__/fast-agent-prompt.test.ts: prompt-assembly assertion for the new rule.

Validation

• vitest run src/server/fast-agent/__tests__/fast-agent-prompt.test.ts in @roomote/cloud-agents: 125 passed.
• oxfmt on both files.

[roomote-community]

No code issues found. See task

_{Reviewed f49619f}